On Tue, Feb 16, 2016 at 4:27 AM, Sagi Grimberg <sagig@xxxxxxxxxxxxxxxxxx> wrote: > >>>> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h >>>> index 4571ef1..b8ff6a3 100644 >>>> --- a/include/linux/blkdev.h >>>> +++ b/include/linux/blkdev.h >>>> @@ -1388,7 +1388,7 @@ static inline bool bvec_gap_to_prev(struct >>>> request_queue *q, >>>> static inline bool bio_will_gap(struct request_queue *q, struct bio >>>> *prev, >>>> struct bio *next) >>>> { >>>> - if (!bio_has_data(prev)) >>>> + if (!bio_has_data(prev) || !queue_virt_boundary(q)) >>>> bio_integrity_add_page return false; >>> >>> >>> >>> Can we not do that? >> >> >> Given there are only 3 drivers which set virt boundary, I think >> it is reasonable to do that. > > > 3 drivers that are really performance critical. I don't think we > should add optimized branching for some of the drivers especially > when the drivers that do set virt_boundary *really* care about latency. > >>> bvec_gap_to_prev is already checking the virt_boundary and I'd sorta >>> like to keep the motivation to optimize bio_get_last_bvec() to be O(1). >> >> >> Currently the approaches I thought of still need to iterate bvec by bvec, >> not sure if O(1) can be reached easily, but I am happy to discuss the >> optimized implementation. > > > Me too. Note that I don't mind if the bio split code won't be optimized, > but I do want req_gap_back_merge/req_gap_front_merge to be... > > Also, are the bvec_gap_to_prev usages in bio_add_pc_page and > bio_integrity_add_page safe? I didn't test this stuff with integrity Yes, because both are non-cloned bvec table. > payloads... Thanks, -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html